In this exploratory research grant application, it is proposed to investigate the applicability of somatic cell nuclear reprogramming to generate otic progenitor cells. It is planned to explore whether induced pluripotent stem cells can be directed to differentiate into inner ear cell types (Specific Aim 1) and in a second set of experiments, it is proposed to investigate conversion of somatic cells directly into progenitors capable of differentiating into hair cell marker expressing cells (Specific Aim 3). An in-depth characterization of the generated cell types is proposed using gene chip technology and comparison of the transcriptional profile of purified embryonic and induced pluripotent stem cell-generated inner ear progenitors with the transcriptional profile of otic placode cells purified from transgenic mice with fluorescent otic placode cells (Specific Aim 2). Knowledge about the potential roles of specific genes gained with somatic cell reprogramming and stem cell guidance will be directly applicable and highly useful for studies focusing on hair cell regeneration in the damaged mammalian organ of Corti as well as for developmental inner ear biology. Moreover, the proposed experiments are highly relevant for potential treatment, where autologous sources of replacement cells are exceedingly desirable to avoid having to immunosuppress the recipient patient. Successful demonstration of applicability of somatic cell nuclear reprogramming to murine inner ear cell regeneration will provide the conceptual basis for future expansion of these experiments to patient-derived somatic cells such as human fibroblasts. Toward finding a treatment for hearing loss, it is proposed to explore the potential of induced pluripotent stem cells that can be generated from somatic cells such as fibroblasts. Specifically it will be tested whether induced pluripotent stem cells can be directed to differentiate into otic cell types, which could be used in future studies with animal models to replace lost cochlear hair cells. This is a highly relevant endeavor because utilization of autologous sources for replacement cells is desirable because these cells could be used without having to immuno-suppress the patient. The research is exploratory as it uses very recently developed novel somatic cell reprogramming technology, which has not been applied to inner ear research. Likewise, it proposes to explore a novel concept to directly convert somatic cells, such as fibroblasts, into inner ear progenitor cells. This direct conversion strategy does not convert the cells completely back into a pluripotent state, but rather into a more restricted state that is potentially already committed to the otic lineage. This novel strategy might bear distinct advantages over the "conventional" strategy, which first converts cells back into an embryonic stem cell state followed by a forward guidance toward a specific organ fate. If successful, this method might as well be applicable to other organs beside the inner ear.